0971 The Pulse of Hypoxia: Event-Related Heart Rate Surges Link Hypoxic Burden to Vascular Damage

Abstract Introduction The respiratory event–specific Heart Rate Delta (ΔHR) reflects the acute autonomic response to intermittent hypoxia and has emerged as a more sensitive risk biomarker than the isolated Apnea-Hypopnea Index (AHI) in Obstructive Sleep Apnea (OSA), especially when analyzed with the hypoxic burden (HB). Objective: To evaluate the association between ΔHR, HB, Oxygen Desaturation Index (ODI), Systolic Blood Pressure (SBP), Dyastolic Blood Pressure (DBP), Mean Blood Pressure (MBP) and Body Mass Index (BMI) in patients with OSA. Methods Methods: This was a cross-sectional study nested within a cohort, where 36 individuals were evaluated, 58.1% of whom were women, with a mean age of 53.95 + 11.86 years. Patients with OSA were included, and measurements were collected for ΔHR, Body Mass Index (BMI), Oxygen Desaturation Index (ODI), SBP, DBP, MBP and HB. HB was measured by considering the area under the curve of oxyhemoglobin desaturation greater than 3%. Results Results: The mean and standard deviation for key variables were: CH 93.07 ± 181.10, sleep ODI 19.89 ± 43.64, ODI 20.65 ± 41.29, minimum HR 52.32 ± 6.95, mean HR 70.09 ± 9.67, maximum HR 110.09 ± 11.71, SBP 134.02 ± 18.98, diastolic blood pressure (DBP) 84.33 ± 14.24. We observed that the correlation of ΔFC with HB (r = 0.630; p = 0.002), ODI (r = 0.643; p = 0.001), sleep ODI (r = 0.667; p = 0.001), age (r = 0.476; p = 0.025), BMI (r = 0.527; p = 0.012), SBP (r = 0.223; p = 0.319), DBP (r = 0.116; p = 0.606), minimum HR (r = 0.028; p = 0.903), maximum HR (r = 0.336; p = 0.015), and MBP (r = 0.188; p = 0.401). Conclusion Conclusion: Individuals with OSA and an elevated ΔHR in the context of a high HB present a higher risk of cardiovascular morbidity and mortality and greater carotid intima-media thickness. This suggests that the integration of ΔHR and HB refines risk stratification beyond AHI and subjective sleepiness, and helps guide who could benefit most from cardioprotective interventions, including CPAP use. Support (if any)